Endless belt for paper or board making machine and a method of weaving cloth therefor



Sept. 2, 1969 x. G. CUMMING 3,464,451

ENDLESS BELT FOR PAPER OR BOARD MAKING MACHINE AND A METHOD OF WEAVINGCLOTH THEREFOR Filed April 28, 1967 4 Sheets-Sheet 1 VAN? flaw/V673146;; 415/29) A ltorney' Sept. 2, 1969 I. G. CUMMING 3,464,461

ENDLESS BELT FOR PAPER OR BOARD MAKING MACHINE AND A METHOD OF WEAVINGCLOTH THEREFOR Filed April 28, 1967 4 Sheets-Sheet z mi 44 /%L r.zlLllwI: 4.1% :1 A 2 1 M 6 Inventor IAN GEORGE CUMMlNG By M A llorneysSept. 2, 1969 G. CUMMING 3,464,451

ENDLESS BELT FOR PAPER OR BOARD MAKING MACHINE AND A METHOD OF WEAVINGCLOTH THEREFOR Filefi April 28, 1967 4 Sheets-Sheet 5 lnvenlor: IANGEORGE CUMMING A Home 32.5

Sept. 2, 1969 G. CUMMING 3,464,451 ENDLESS BELT FOR PAPER 0R BOARDMAKING MACHINE AND A METHOD OF WEAVING CLOTH THEREFOR Filed April 28,1967 4 Sheets-Sheet 4 lnvenlor IAN GEORGE. CUMMING By W? Attorneys UniteY ABSTRACT OF THE DISCLOSURE Woven cloth for an endless belt for a paperor board making machine is a twill woven cloth and the twill pattern isreversed at intervals of from two inches to four feet. Each warp of thecloth then forms throughout its length a series of substantiallychevron-shaped formations transversely directed in the plane of thecloth.

A loom for weaving the cloth is provided with means for reversing theoperation of the heddle frames of the loom at the required intervals soas to reverse the twill pattern.

This invention relates to woven cloth for endless belts for paper orboard making machines, and to a method of making such cloth.

Such belts are used on the wet end of Fourdrinier paper or board makingmachines to convey and dewater paper pulp so as to form a mat or sheetof fibres. The cloth may be woven with metal or synthetic warps andwefts, or with metal warps and synthetic wefts, or with synthetic warpsand metal wefts, the belt being formed by joining together the ends ofthe cloth with the warps running lengthwise of the belt.

Due to the woven construction, the warps form knuckles on the undersideand topside of the woven belt, and, in operation, the underside warpknuckles are subjected to severe abrasive wear as the belt travels oversuction boxes and other stationary surfaces such as forming boards andfoils which are fitted to the paper or board making machine.Furthermore, on Inverform Machines, very severe abrasive wear is causedby the autoslice blades.

Under certain conditions, the warp knuckles wear grooves in the surfaceof the tops of the suction boxes and on the leading edges of theautoslice blade, and these grooves are a replica of the longitudinalpattern of the underside warp knuckles.

A grooved suction box top may result in a very serious shortening of thelife of the belt and create faults in the paper or board being made.

In operation, there is a tendency for the belt to move to one side orthe other of the paper or board making machine under the action of guiderolls. When a suction box top is grooved, the belt hangs on the box andresists the normal lateral movement of the belt. Increasing lateralforce is built up by automatic guide rolls causing severe lateral thruston the warp knuckles in the grooves and severe wear on the sides of theknuckles. If the belt is released from the grooves due either tosufiicient lateral pressure or to the presence of a discontinuity in thepattern of the underside warp knuckles, as for example at the joint orseam which makes the belt endless, the belt slides over the top of thegrooves which rasp the warp knuckles, causing further wear andfrequently a disturbance in the uniformity of the sheet formation.

A grooved suction box top also causes serious trouble States Patent Owhen a new belt is fitted. Differences in warp pattern in relation tothe grooves cause severe local Wear and drastically reduces the life ofthe belt.

This problem in the operation of paper machine belts has been known formany years by paper and board machine belt manufacturers, paper andboard machine builders and paper and board makers, and while variousmethods of overcoming the ditficulty have been proposed and practised,and some success has been achieved, these methods have not been entirelysuccessful or have involved additional handling of the cloth afterweaving and a further stage in the process of finishing the cloth orforming the belt.

An object of the present invention is to provide cloth, which, whenformed into a belt and used on a paper making machine as aforesaid, doesnot form grooves in the tops of the suction boxes and does not reactundesirably to grooves previously formed thereon, or which has a lessertendency to do so than belts hitherto used.

According to the present invention we provide twill woven cloth forforming or formed into an endless belt for a paper or board makingmachine in which the twill pattern is reversed at predeterminedintervals so that each warp forms throughout its length a series ofsubstantially chevron-shaped formations transversely directed in theplane of the cloth.

Further, according to the present invention we provide a method ofweaving twill cloth for an endless belt for a paper or board makingmachine comprising reversing the twill pattern at predeterminedintervals so that each warp forms throughout its length a series ofsubstantially chevron-shaped formations transversely directed in theplane of the cloth.

Still further, according to the present invention we provide a loom forweaving twill cloth for endless belts for paper or board making machinesin which there is provided apparatus adapted and arranged so as toreverse the operation of the heddle frames at predetermined intervals.

Said apparatus may comprise forward and reverse drives from the mainshaft of the loom to the heddle cam shaft, a clutch for effectingengagement of one or other of said drives, a clutch-actuating device,and a time switch device controlling the latter so that the said drivesengage alternately at predetermined intervals.

An embodiment of the invention will now be described by way of example,with reference to the accompanying drawings, in which:

FIG. 1 shows schematically a plan view of a typical conventionally woventhree shed twill paper or board making belt, in which the twill patternA -A is going from right to left when viewed in the direction of thearrow,

FIG. 2 is a fragmentary view corresponding to FIG. 1, to a larger scale,the twill pattern A A going from right to left when viewed in thedirection of the arrow,

FIG. 3 shows the top surface of a typical conventionally woven threeshed twill, in which the twill pattern A A is going from left to rightwhen viewed in the direction of the arrow,

FIG. 4 shows the top surfaces of a panel of cloth in accordance with thepresent invention, in which the twill patterns A A A A and A -A arereversed from left to right to right to left and then to left to rightwhen viewed in the direction of the arrow,

FIG. 5 shows a diagrammatic view of apparatus for effecting the changein sequence of heddle reciprocation in a loom so as to reverse the twillpattern, and

FIG. 6 shows a diagrammatic side view of the cams and heddlearrangements in a loom.

In FIG. 1 the warps run parallel to the running axis 27 of the wet endof a paper or board making machine. The seam 28 is constructed in theusual welded, soldered or sewn manner and runs at an angle to thetransverse axis 29 of the belt, the axis 29 being at right angles to theaxis 27. In a typical twill weave each warp is interlaced with the weftso that it passes over one weft and under the next two. Adjacent warpsfollow the same pattern of interlacing but are arranged to be out ofphase with each other by one weft. In such a twill woven cloth, thetopside knuckles of a series of adjacent warps created by passing overwefts follow diagonal lines A A across the width of the cloth.

The details of weave shown in FIG. 1 is shown in FIG. 2, and the patterncan be changed to form a line of knuckles running in a diagonallyopposite direction A A across .the cloth by changing the pattern ofinterlacing as shown in FIG. 3.

It has now been found that, if the twill pattern is changed at regularintervals, the warps follow a chevron or zig-zig pattern, as shown inFIG. 4. The angle of slope is influenced by the flexibility of the warpand weft, the diameter of the warp and weft and the numbers of warps andwefts per inch. In FIGS. 2, 3, and 4, the warps are indicated by thenumeral 25, and the wefts by the numeral 26.

In its simplest form, weaving consists of taking every alternate warpand holding it apart from the intervening warps so that the weft maythus be placed. The alternate warps are then crossed over the weft whichhas just been placed and another weft is placed. The process repeats anda plain woven cloth results. In this example, the two groups into whichthe warps are divided are known as sheds. To form twill, it is necessaryto divide the warps into a minimum of three sheds. The sheds are createdby threading each warp through a heddle and the heddles corresponding tothe warps of one shed are held in one frame whilst the heddlescorresponding to the warps of the other sheds are held in other frames.The number of frames is determined by the number of sheds required. In athree shed twill, for example, it is necessary to have three heddleframes as shown in FIG. 6 at 1, 2 and 3. In order that the warps andwefts may be interlaced it is necessary for the heddle frames 1, 2, 3 toreciprocate vertically. This is arranged by a system of levers known astreadles and shown in FIG. 6 at 24 which are articulated by a bank ofcams 23, FIG. 5. There are two treadles 24 to each heddle frame and onecam 23 to each treadle 24. In a three shed twill in which the warps passover one weft and under two, the cycle for each heddle frame is suchthat the frame is held down whilst two wefts are placed and is held upwhilst a third weft is placed. The sequence of operation is such thatfor the first weft the first frame is up whilst the second and thirdframes are down. The second frame comes up for the second weft and thefirst and third remain down. The first cycle is complete after the nextmove when the third frame comes up for the third weft and the first andsecond stay down. This sequence of operation creates a slope in thewarps, as already described, in one direction. A slope in a diagonallyopposite direction is obtained by precisely reversing the sequence sothat, after the first frame has been up, the third frame comes up whilstthe first and second stay down. Next, the second frame comes up whilstthe first and third stay down. In FIG. 6, 30 indicates the warp beam, 32indicate warps in a shed, 33 indicates the woven cloth, and 34 the clothbeam.

This reversal action is achieved in a loom as follows:

The mainshaft 4 is a constantly rotating shaft, running at half the loomspeed, and the heddle cam shaft 5 is driven from the mainshaft 4 throughtwo spur gear wheels 9, or a chain and chain wheels 11, 12. The ratiosof the spur gears and chain wheels are identical and in this embodimenteach ratio is 1.5/1.

The spur gear 9 and chain wheel 11 are both free to rotate on themainshaft 4 but are held in a fixed position along the mainshaft 4 bysplit thrust and journal bearings 13. The gear wheel 10 and the chainwheel 12 are both fixed to the heddle cam shaft 5, and the latter drivesthe heddle cams 23 which in turn actuate the heddle frames 1, 2 and 3carrying the warps.

Between the wheels 9 and 11 on the mainshaft 4 there is a clutch member6 which rotates with and is movable along the mainshaft 4 on a slidingkey. When the clutch 6 is moved from left to right in FIG. 5 it engagesa clutch member 8 and disengages a clutch member 7. The members 7 and 8are fixed to the gear wheel 9 and chain wheel 11 respectively. As can beseen, if clutch member 6 is moved from engagement with the member 7 intoengagement with the member 8, the shaft 5 changes direction of rotation.

The clutch member 6 is moved along shaft 4 by means of a rod 18A of apiston in an air cylinder 18 pushing or pulling a lever 17 which ispivotally mounted at 14. Clutch shoes 15 are pivotally attached to thelever 17 and fit into an annular recess 16 in the clutch member 6. Theinternal faces of the clutch members 7 and 8 have teeth 19 which engagewith similar teeth on the external faces of the member 6.

A sequence-timing device 20 is provided for counting a predeterminednumber of wefts inserted and is actuated by a drive 21 fixed to theshaft 4. When the device 20 reaches a pre-set number, the device 20through connections 20a actuates a controller 41 which is connected tothe drive unit '42 for the main shaft 4 and is also connected throughconnections 22a to a solenoid-controlled valve 22 for the air cylinder18. When the device 20 triggers the controller 41, it operates throughthe drive unit 42 to arrest the drive to the shaft 4 to stop the loom,and then after a timed delay of two to three seconds, the controller 41energizes the solenoid-controlled valve 22, for example, as shown inFIG. 5, to retract the rod 18A and move the lever 17 from left to right,thus first disengaging the gear drive 9, 10 and thereafter engaging thechain wheel drive 11, 12. The loom is then restarted automatically tocontinue weaving with a reversed twill pattern. When the next pre-setnumber is reached, the device 20 again actuates the controller 41 whichthereagain stops the loom and after a timed delay of two to threeseconds de-energizes the solenoid valve 22 to thereby extend the rod 18Ato shift the lever 17 from right to left, first disengaging the chainwheel drive 11, 12 and then engaging the gear drive 9, 10. The loom isthen restarted automatically with the result that the twill patternweave is again reversed and returns to the original direction. Thedevice 20 then counts a predetermined number of wefts and the operationis repeated so that the direction of the twill pattern is reversed inalternation throughout the length of the cloth.

As an example of the effect of reversing the pattern of a three shedtwill, a typical cloth containing 60 warps of 0.00% inch dia. to theinch and 45 wefts of 0.0108 inch dia. to the inch develops a slope ofone-sixth of an inch in 9 inches of cloth if the twill pattern isreversed at 9 inch intervals. Expressing this another way the anglesubtended at the apex of each chevron is 178 C.

The foregoing example is not to be held to imply that the invention islimited to a particular twill specification, nor to a particulardistance between reversals of the twill pattern. According to theconditions encountered on a paper or board making machine, the distancebetween reversals may be varied from 2 inches to 4 feet with advantageand the twill specification may be selected from the full range oftwills which it is possible to weave.

The invention uses in a controlled manner the phenomenon that the warpsand wefts of cloth woven in a twill pattern in a normal state ofequilibrium do not lie at right angles to each other. The following isan example of this phenomenon. When a length of twill cloth woven withthe same pattern throughout its length is laid out flat it forms aparallelogram. If such a piece of twill woven cloth is formed into anendless belt the line of the joint forms an angle with the transverseaxis of the belt. When such a belt is used on a paper or board machine,the warp lies parallel to the running axis of the wet end of the paperor board making machine and the weft lies parallel to the seam or joint.

Thus, if a length of twill woven cloth is woven in a series of sectionsin which the twill pattern is reversed in each section by reversing thesequence of operation of the heddles of the loom, the wefts at the pointof reversal lie parallel to the transverse axis and the warps changedirection so as to lie at alternate opposite angles to the runing axis.By joining the ends of such cloth, an endless belt is formed, in whicheach warp forms throughout its length a series of substantiallychevron-shaped formations transversely directed in the plane of thecloth.

The cloth may be, for example from 40 to 110 mesh.

I claim:

1. In an endless belt for a paper making machine made of twill wovencloth, said belt having warps extending throughout the length of thebelt and wefts extending across the width of the belt, the improvementconsisting in that the cloth comprises a series of sections throughoutthe length of the belt and the twill pattern is reversed betweensuccessive sections, whereby each warp forms throughout its length aseries of substantially chevronshaped formations transversely directedin the plane of the cloth.

2. An endless belt as claimed in claim 1, in which the twill pattern isreversed at from two inch to four foot intervals, and the cloth is from40 to 110 mesh.

3. An endless belt as claimed in claim 1, in which the twill pattern isreversed at 9" intervals, and the angle subtended at the apex of eachchevron is 178.

4. In a method of weaving twill cloth and forming therefrom an endlessbelt for a paper making machine, said belt having warps extendingthroughout the length of the belt and wefts extending across the widthof the belt, the steps of weaving the cloth in a series of sectionsthroughout the length of the belt, and reversing the twill patternbetween successive sections whereby each warp forms throughout itslength a series of substantially chevron-shaped formations transverselydirected in the plane of the cloth.

5. The method claimed in claim 4, in which the reversal of the twillpattern is effected by reversing at predetermined intervals theoperation of the heddle frames of the loom on which the cloth is beingwoven.

6. The method claimed in claim 4, in which the twill pattern is reversedat from two inch to four foot intervals and the cloth is 40 to mesh.

7. The method claimed in claim 4, in which the twill pattern is reversedat 9" intervals, and the angle subtended at the apex of each chevron is178.

8. Twill woven Fourdrinier cloth having a series of sections throughoutits length, warps extending through said series of sections, and weftsextending across the width of the cloth, in which the twill pattern isreversed between successive sections, whereby each warp forms throughoutits length a series of substantially chevronshaped formationstransversely directed in the plane of the cloth.

References Cited UNITED STATES PATENTS 1,587,338 6/1926 Lindsay 139-42552,143,552 1/1939 Green 139-4255 2,152,982 4/1939 Watson et al. 139-802,227,669 1/1941 Parrett 139-4255 2,903,021 9/1959 Holden et al.139-4255 3,139,119 6/1964 Buchanan 139-4255 3,211,606 10/1965 Watson139-4255 3,214,818 11/ 1965 'Ewen.

FOREIGN PATENTS 1,296,090 5/ 1962 France.

427,915 5/1935 Great Britain.

OTHER REFERENCES The Cambridge Wire Cloth Company, pp. 1 and 14, recdUS. Patent Office Feb. 19, 1932.

JAMES KEE CHI, Primary Examiner US. Cl. X.R. 139-80; 245-8

